Conventionally, as an electrically-powered vehicle configured to be capable of generating a vehicle drive force using electric power from a vehicle-mounted power storage device, the one equipped with a vehicle state display device that determines a remaining travelable distance, which indicates how much farther the vehicle can travel, based on a remaining capacity (SOC: State of Charge) of the vehicle-mounted power storage device, and displays the remaining travelable distance on a display unit has been used. Further, a vehicle using an internal combustion engine as a motive power source also has a vehicle state display device that determines a remaining travelable distance based on a remaining amount of fuel, and displays the remaining travelable distance on a display unit.
As the vehicle state display device mounted in a vehicle using an internal combustion engine as a motive power source, for example, in Japanese Patent Laying-Open No. 2004-254483 (PTD 1), if deterioration in function occurs in a power supply system such as a battery and an alternator for supplying electric power to an EFI system having an injector injecting fuel to an internal combustion engine and electric components such as various sensors, and the like, a vehicle state display device displays a remaining travelable distance of a vehicle limited due to the deterioration in function on a display unit. In PTD 1, if deterioration in function occurs in the power supply system, firstly, a remaining capacity of the battery and a discharged current in that state are detected. Then, a remaining travelable time indicating how much longer the internal combustion engine can be driven continuously is calculated based on the detected remaining capacity of the battery and discharged current. Further, a remaining travelable distance is calculated based on the calculated remaining travelable time and an average vehicle speed of the vehicle.